This revised proposal seeks support for the Gene Library Resource for the purple sea urchin, Strongylocentrotus purpuratus. This Resource provides the essential infrastructure, new technology, molecular biology support services, and both material and informational resources for the whole field of sea urchin research. The Resource is unique in the world, and it is fair to state that directly or indirectly it has impacted every sea urchin laboratory in the US and elsewhere as well. In the last five years the P40 provided essential technological and material support that made it possible for HGRI to obtain the genomic sequence of S. purpuratus. This animal has become a major research model, and knowledge of the genomically encoded regulatory networks underlying development of its embryo is more advanced than for any other animal system. Recently, HGRI approved support for sequencing of several further echinoderm species (at the Human Genome Sequencing Center, Baylor College School of Medicine). This decision was taken because of the major scientific advantages that would be available for the research community were the genomes of these additional echinoderm species for comparative studies of gene regulatory network organization, for cis-regulatory structure-function studies, and for research on mechanisms of embryonic and postembryonic development. But research model systems are useful in these fields only if the biological parameters of operation in the system as well as the sequence of the genome are in hand. The service and research objectives of the present renewal application thus fall into two broad components: to further support and develop the S. purpuratus research resource, by provision of advanced technologies and databases, and to establish equivalent technological and biological as well as material resources for the additional echinoderm species, while providing essential support for the genome sequencing efforts now being directed at these species. The initial set of additional species with which we are here concerned, all excellent laboratory animals, are a sea star, Asterina miniata, another very widely used sea urchin, Lytechinus varieaatus, and a distantly diverged echinoid, Eucidaris tribuloides.